Line spacing device for typewriters

ABSTRACT

A carrier lever on which a pawl, engaging the line space ratchet of a turnable platen, is movably mounted, is shifted a predetermined angle until blocked by a rigid stop so that the platen is turned to a desired position. Due to inertia, the platen with the ratchet moves beyond the desired position, but an elastic stop is engaged by the pawl when the carrier lever is blocked so that the inertial movement causes deformation of the elastic stop which turns the ratchet and platen by means of the pawl back to the desired position. A spring connecting the pawl with the carrier lever also opposes the inertia movement.

United States Patent [191 Kunst et al.

[ Oct. 9, 1973 LINE SPACING DEVICE FOR TYPEWRITERS [75] Inventors: Detlef Kunst; Hans Fuchs, both of Wilhelmshaven, Germany U [73] Assignee: Olympia Werke AG,

Wilhelmshaven, Germany 22 Filed: n.20,1971

21 Appl. No.: 210,012

[30] Foreign Application Priority Data Dec. 22, 1970 Germany P 20 63 062.0

[52] US. Cl. 197/114, 197/183 [51] Int. Cl B41] 19/76 [58] Field of Search 197/114, 183

[56] References Cited UNITED STATES PATENTS 727,001 5/1903 Shepard 197/183 X 2,992,719

7/1961 Keller 197/114 R 3/1964 Tibbling 197/114 R X 12/1964 Hoysak 197/114 R Primary Examiner-Ernest T. Wright, Jr. Attorney-Michael S. Striker 5 7] ABSTRACT A carrier lever on which a pawl, engaging the line space ratchet of a turnable platen, is movably mounted, is shifted a predetermined angle until blocked by a rigid stop so that the platen is turned to a desired position. Due to inertia, the platen with the ratchet moves beyond the desired position, but an elastic stop is engaged by the pawl when the carrier lever is blocked so that the inertial movement causes deformation of the elastic stop which turns the ratchet and platen by means of the pawl back to the desired position. A spring connecting the pawl with the carrier lever also opposes the inertia movement.

10 Claims, 2 Drawing Figures BACKGROUND OF THE INVENTION The present invention is concerned with a typewriter, accounting machine, or similar office machine which has .a turnable platen with a line space ratchet, and a carrier lever with a pawl turnable about the axis of the platen while the pawl cooperates with the line space ratchet for shifting the platen with paper sheets thereon, to a new line position.

Line spacing devices are known in which arresting means are provided cooperating with the line space ratchet of the platen. The purpose of the arresting means is to prevent an inertial movement of the platen beyond the correct shifted position, and a displacement of the paper sheets on the platen relative to eachother.

It has been found that such a relative sliding of the paper sheets on the platen, is not improvedby rapidly braking the platen by the arresting means so that the appearance of the text on the paper sheets is detrimentally affected.

SUMMARY OF THE INVENTION It is one object of the invention to provide a line spacing device which is free of the disadvantages of the prior art, and particularly prevents a relative displace ment of paper sheets between each other and on the platen.

Another object of the invention is to brake inertial movement of the platen by a resilient stop which returns the platen to the desired position.

With these objects in view, the pawl, which cooper ates with the line space ratchet on the platen, is'

mounted on a carrier lever for translatory and angular movement, and a first stop blocks the carrier lever while a second stop blocks the pawl.

Due to the provision of two stops or blocking means, the maximum acceleration of the platen with the ratchet is reduced before the pawl arrives in its end position. Preferably, a pin-and-slot connection mounts the pawl on the carrier lever, and thestop whichblocks the pawl in the end position is elastic. Due to the reduction of the platen acceleration, the effect of inertia on the paper sheets is eliminated so that the paper sheets cannot be displaced relative to each other or to the platen.

An embodiment of the invention comprises a platen and a line space ratchet secured to the platen for rotation together; carrier means, preferably an angular lever, which is moved by operating means under the control of a line spacing key between first and second positions; rigid blocking means or stop means for blocking the carrier means in the second position; arresting means, preferably a pawl mounted on the carrier means for movement with the same, and also for movement relative to the same; biassing means, preferably including two springs connecting the arresting means with the carrier means so that the first spring urges the carrier means to engage the line space ratchet so that the line space ratchet and platen are angularly shifted the predetermined angle to a desired position; and an elastic stop means engaged by the arresting means in the second position of the carrier means.

The elastic stop means is resiliently deformed when the platen and line space ratchet move by inertia beyond the desired position and displace the arresting means relative to the blocked carrier means until the also by the second spring.

In the preferred embodiment, a pin and slot connection is providedbetween the arresting means in the form of an arresting pawl, and a carrier means in the form of an angular lever.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with a additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a fragmentary side view of an embodiment of the invention in a position of rest shown in chain lines, and a shifted operative position shown in solid lines; and

FIG. 2 is a side view of the embodiment of FIG. 1, illustrating a position obtained by the inertial movement of the platen.

DESCRIPTION OF THE PREFERRED EMBODIMENT which a rope 7 is guided, one end of which is secured to a stationary wall 70, while the other end is operated under the control of line spacing means, not shown, in the usual manner. When rope 7 ispulled, carrier lever 5 moves a predetermined angle from the position shown in chain lines to the position shown in solid lines.

The arm 5b of carrier lever 5 carries a fixed pin 5c which is guided in a straight slot of an arresting means or arresting pawl 8 which has a tooth 8b. A tension spring 9 is secured at one end to the end portion of arrestingpawl 8, and at the other end to the pin 5c and to the carrier lever 5.Consequently, arresting pawl 8 assumes a position in which one end of slot 8a abuts pin 50. A torsion spring 10 hastwo ends hooked over edges of arm 5b and arresting pawl 8, and urges arresting pawl 8 to turn about pin 50 to a positionin which tooth 8b engages a recess of the line space ratchet 4 when carrier lever 5 is in the position shown in solid lines in FIG. 1. When carrier lever 5 is in the position shown, in chain lines in FIG. 1, torsion spring 10 also urges arresting pawl 8 to-turn in counterclockwise direction, but tooth 8b engages the sliding face 11a of an angularly adjustable member 11 which is mounted for turning movement on shaft 2, and permits in the usual manner selection of the angle which platen 3 is shifted between successive line positions.

An elastic stop means in the form of a block 15 consisting of elastic material is secured to a bracket 15a on a side wall I of the carriage.

The line spacing apparatus illustrated in FIGS. 1 and 2 operates as follows:

In the position of rest of carrier lever shown in chain lines in FIG. I, tooth 8b of arresting pawl 8 engages the slide surface Ila of member 11. Spring 9 has pulled arresting pawl 8 to a position in which one end of slot 80 abuts pin 5c carried by arm 51) of angular carrier lever 5. Arm 5b is spaced from the rigid stop 14, and the abutment face 8c of arresting pawl 8 is spaced from the abutment face 15b of the elastic stop 15. I

In order to start the line spacing operation, the line spacing means, not shown, of the typewriter, are actuated to exert a pull on the rope 7 of the operating means 7, 6, 70 so that the carrier lever 5 is turned from the first end position shown in chain lines in FIG. I, to the second end position shown in solid lines so that carrier lever 5 moves through a predetermined angle which is exactly determined by adjustment of the position of the blocking means 14 by screw 13.

During this angular movement in counterclockwise direction, the arresting pawl 8 moves with carrier lever 5, and its tooth 8b first slides on the slide surface 11a of member 11 by whose angular position the number of steps which platen 3 is shifted is determined in the usual manner. When tooth 8b moves off slide face Ila, it is urged by torsion spring to engage the notch of line space ratchet 4 following the slide surface lla, so that during further movement of carrier lever 5 to the second end positon, ratchet 4 with platen 3 are turned the predetermined angle. Directly after the carrier lever 5 is stopped by blocking means 14, the abutment face Sr: of arresting pawl 8 engages the abutment face b of the elastic stop 15 since platen 3 with ratchet 4 continue to rotate due to the great inertia of platen 3. Such inertial movement is transmitted from the ratchet 4 to the arresting pawl 8 which is displaced to the position shown in FIG. 2 in which the end of slot 8a has been moved away from pin 5c which is fixed on the blocked arm 5b of carrier lever 5. This displacement of arresting pawl 8 has tensioned spring 9, while at the same time, the elastic stop 15 is resiliently compressed so that the movement of arresting pawl 8 is dampened so that the movement of the ratchet 4 and of platen 3 due to inertia is less than the distance between two teeth of ratchet 4.

The stored energy of the turned ratchet 4, which causes inertial movement beyond the desired position, is consumed by spring 9 and resilient stop 15 which both tend to return the arresting pawl 8 to its normal position shown in solid lines in FIG. 1 in which the end of slot 8a abuts pin 5c. While arresting pawl 8 is returned by spring 9 and resilient stop 15 to its normal position, tooth 8b acts through ratchet 4 on platen 3 to turn the same less than one ratchet step in clockwise direction to the desired position which is reached when the pin 5c and slot 8a are in the normal position shown in solid lines in FIG. 1. During the return of arresting pawl 8 to its normal position, the angular carrier lever 5 remains in its second end position abutting blocking means 14 so that platen 3 is in the desired correct position having turned the same predetermined predetermined angle as carrier lever 5, when arresting pawl 8 is in the normal position shown in solid lines in FIG. 1. When the rope 7 is then released, the carrier lever 5 together with the arresting pawl 8 thereon, is returned to the position of rest shown in chain lines in FIG. 1.

The above-described simple, but reliably operating line spacing device permits line spacing operations at a very high speed of the carrier means or lever 5 while a displacement of paper sheets relative to the carriage at the end of the line shifting operation is prevented, which results in a pleasing appearance of the typed text, and assures accurate copies if several carbon copies are made of the typed text.

Furthermore, the line spacing device of the present invention operates at such a high speed that it can be used in power driven typewriters.

As is apparent from the drawing, the line spacing device has comparatively few parts, and is compact so that little space is taken up in the typewriter.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other type of line spacing devices differing from the types described above.

While the invention has been illustrated and described as embodied in a line spacing device including a biassed pawl on a carrier lever, a rigid blocking means for the carrier lever, and a resilient stop for the pawl, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Line spacing device for typewriters, comprising supporting means; a platen and a line space ratchet mounted on said supporting means for rotation together; carrier means mounted on said supporting means for angularly moving a predetermined angle between first and second end positions; operating means for moving said carrier means between said first and second end positions; blocking means for blocking said carrier means in said second position; arresting means mounted on said carrier means for movement with said carrier means and also for movement relative to said carrier means; biassing means connecting said arresting means with said carrier means for urging said arresting means to a normal position abutting said carrier means and engaging said line space ratchet so that said line space ratchet and said platen are angularly shifted said predetennined angle to a desired position by movement of said carrier means from said first end position to said second end position; and a stop means engaged by said arresting means when said carrier means is blocked in said second end position and said platen and line space ratchet move due to inertia beyond said desired position and displace said arresting means relative to said blocked carrier means 'out of said normal position until said platen, line space ratchet, and arresting means are stopped by said stop meanswhereupon said platen is returned with said line space ratchet to said desired position by said arresting means returned by said biassing means to said normal position.

2. Line spacing device for typewriters comprising supporting means; a platen, and a line space ratchet secured to said platen, mounted on said supporting means for rotation together; carrier means mounted on said supporting means for angularly moving a predetermined angle between first and second positions; operating means for moving said carrier means between said first and second positions; rigid blocking means for blocking said carrier means in said second position; arresting means mounted on said carrier means for movement with the carrier means, and also for movement relative to the carrier means; biassing means connecting said arresting means with said carrier means for urging said arresting means to a normal position engaging said line space ratchet so that said line space ratchet and said platen are angularly shifted said perdetermined angle to a desired position by movement of said carrier means from said first position to said second position; and an elastic stop means engaged by said arresting means in said second position of said carrier means and being resiliently deformed when said platen and line space ratchet move due to inertia beyond said desired position and displace said arresting means relative to said blocked carrier means until said platen, said line space ratchet, and said arresting means are stopped by said deformed elastic stop means whereupon said platen is returned with said line space ratchet to said desired position by said elastic stop means assuming a normal 'undeformed position and acting on said arresting means.

3. Line spacing device as claimed in claim 2 wherein said carrier means includes means for mounting said arresting means for translatory movement and turning movement; wherein said biassing means includes a first spring means biassing said arresting means to turn on said mounting means to engage said line space ratchet,

and a second spring means for biassing said arresting means to move in said translatory movement to said normal position abutting said carrier means; and wherein said arresting means, displaced by said line space ratchet and platen moving beyond said desired position, tensions said second spring means so that said arresting means is returned to said normal position by said second spring means for returning said platen and line space ratchet to said desired position.

4. Line spacing device as claimed in claim 3 wherein said mounting means includes a pin and slot connection between said carrier means and said arresting means; wherein said second spring means connects said arresting means with said carrier means and urges said arresting means to said normal position in which the pin abuts one end of the slot of said pin and slot connection; and wherein said one end of said slot moves away from said pin during inertia movement of said platen and line space ratchet with said arresting means.

5. Line spacing device as claimed in claim 4 wherein said supporting means includes a rotatable shaft fixedly supporting said platen and said line space ratchet; wherein said carrier means includes a lever rotatably mounted on said shaft and having said pin; and wherein said arresting means has said slot of said pin and slot connection.

'6. Line spacing device as claimed in claim 5 wherein said first spring means includes a torsion spring connecting said arresting means with said carrier means; and wherein said second spring means includes a tension spring connecting said pin with said arresting means.

7. Line spacing device as claimed in claim 2 wherein said elastic stop means includes a block secured to said supporting means and consisting of an elastic material.

8. Line spacing device as claimed in claim 2 comprising means for adjusting the position of said rigid blocking means for varying said second position of said carrier means and thereby said desired position of said platen.

9. Line spacing device as claimed in claim 1 wherein said supporting means include a rotatable shaft fixedly supporting said platen and said line space ratchet; wherein said carrier means includes lever means mounted on said shaft for angular movement between said first and second end positions; wherein said arresting means includes a pawl having a tooth for engaging said line space ratchet; wherein said pawl is mounted on said lever means for translatory movement and angular movement; wherein said biassing means include a first spring for turning said pawl to engage with said tooth said line space ratchet, and a second spring for urging said pawl to move in said translatory movement to said normal position abutting said lever means; and wherein said operating means are connected with said lever means for turning said lever means with said pawl between said first and second end positions.

10. Line spacing device as claimed in claim I wherein said arresting means include a pawl mounted on said carrier means and having on one side an abutment face and on the other side a tooth for engaging said line space ratchet; wherein said stop means includes a resilient block having an abutment face engaged by said abutment face of said pawl when said carrier means is stopped in said second end position. 

1. Line spacing device for typewriters, comprising supporting means; a platen and a line space ratchet mounted on said supporting means for rotation together; carrier means mounted on said supporting means for angularly moving a predetermined angle between first and second end positions; operating means for moving said carrier means between said first and second end positions; blocking means for blocking said carrier means in said second position; arresting means mounted on said carrier means for movement with said carrier means and also for movement relative to said carrier means; biassing means connecting said arresting means with said carrier means for urging said arresting means to a normal position abutting said carrier means and engaging said line space ratchet so that said line space ratchet and said platen are angularly shifted said predetermined angle to a desired position by movement of said carrier means from said first end position to said second end position; and a stop means engaged by said arresting means when said carrier means is blocked in said second end position and said platen and line space ratchet move due to inertia beyond said desired position and displace said arresting means relative to said blocked carrier means out of said normal position until said platen, line space ratchet, and arresting means are stopped by said stop means whereupon said platen is returned with said line space ratchet to said desired position by said arresting means returned by said biassing means to said normal position.
 2. Line spacing device for typewriters comprising supporting means; a platen, and a line space ratchet secured to said platen, mounted on said supporting means for rotation together; carrier means mounted on said supporting means for angularly moving a predetermined angle between first and second positions; operating means for moving said carrier means between said first and second positions; rigid blocking means for blocking said carrier means in said second position; arresting means mounted on said carrier means for movement with the carrier means, and also for movement relative to the carrier means; biassing means connecting said arresting means with said carrier means for urging said arresting means to a normal position engaging said line space ratchet so that said line space ratchet and said platen are angularly shifted said perdetermined angle to a desired position by movement of said carrier means from said first position to said second position; and an elastic stop means engaged by said arresting means in said secOnd position of said carrier means and being resiliently deformed when said platen and line space ratchet move due to inertia beyond said desired position and displace said arresting means relative to said blocked carrier means until said platen, said line space ratchet, and said arresting means are stopped by said deformed elastic stop means whereupon said platen is returned with said line space ratchet to said desired position by said elastic stop means assuming a normal undeformed position and acting on said arresting means.
 3. Line spacing device as claimed in claim 2 wherein said carrier means includes means for mounting said arresting means for translatory movement and turning movement; wherein said biassing means includes a first spring means biassing said arresting means to turn on said mounting means to engage said line space ratchet, and a second spring means for biassing said arresting means to move in said translatory movement to said normal position abutting said carrier means; and wherein said arresting means, displaced by said line space ratchet and platen moving beyond said desired position, tensions said second spring means so that said arresting means is returned to said normal position by said second spring means for returning said platen and line space ratchet to said desired position.
 4. Line spacing device as claimed in claim 3 wherein said mounting means includes a pin and slot connection between said carrier means and said arresting means; wherein said second spring means connects said arresting means with said carrier means and urges said arresting means to said normal position in which the pin abuts one end of the slot of said pin and slot connection; and wherein said one end of said slot moves away from said pin during inertia movement of said platen and line space ratchet with said arresting means.
 5. Line spacing device as claimed in claim 4 wherein said supporting means includes a rotatable shaft fixedly supporting said platen and said line space ratchet; wherein said carrier means includes a lever rotatably mounted on said shaft and having said pin; and wherein said arresting means has said slot of said pin and slot connection.
 6. Line spacing device as claimed in claim 5 wherein said first spring means includes a torsion spring connecting said arresting means with said carrier means; and wherein said second spring means includes a tension spring connecting said pin with said arresting means.
 7. Line spacing device as claimed in claim 2 wherein said elastic stop means includes a block secured to said supporting means and consisting of an elastic material.
 8. Line spacing device as claimed in claim 2 comprising means for adjusting the position of said rigid blocking means for varying said second position of said carrier means and thereby said desired position of said platen.
 9. Line spacing device as claimed in claim 1 wherein said supporting means include a rotatable shaft fixedly supporting said platen and said line space ratchet; wherein said carrier means includes lever means mounted on said shaft for angular movement between said first and second end positions; wherein said arresting means includes a pawl having a tooth for engaging said line space ratchet; wherein said pawl is mounted on said lever means for translatory movement and angular movement; wherein said biassing means include a first spring for turning said pawl to engage with said tooth said line space ratchet, and a second spring for urging said pawl to move in said translatory movement to said normal position abutting said lever means; and wherein said operating means are connected with said lever means for turning said lever means with said pawl between said first and second end positions.
 10. Line spacing device as claimed in claim 1 wherein said arresting means include a pawl mounted on said carrier means and having on one side an abutment face and on the other side a tooth for engaging said line space ratchet; wherein said stop Means includes a resilient block having an abutment face engaged by said abutment face of said pawl when said carrier means is stopped in said second end position. 